The FAA RFH (http://www.faa.gov/library/manuals/aircraft/media/faa-
h-8083-21.pdf) only mentions yaw strings on gyroplanes, so I added
that. Find a ref for helicopters, and add the info to the WP article.


On Jan 29, 8:19 pm, "COLIN LAMB" wrote:
and no, the "downwash" does not render them useful.I should read twice and send once. I meant:

does not render them useless.

Time for a soda.

Colin